In complex data networks, the operation of data plane involving switches or routers depends heavily on the operational functionality of the associated control plane. Indeed, providing redundancy and low latency failover of control plane is important to minimizing data network downtime and maintaining the network availability which is generally costly and complex to implement and support.
In a deployed wireless local area network (WLAN) supporting layer-3 mobility, there are three main components including Access Points (APs), Wireless Domain Service (WDS) on the Wireless LAN Service Module (WLSM), and Layer-3 Mobility Module (L3MM) on Route Processor. The Access Point (AP) in the wireless LAN is configured to provide a communication link (for example, a radio connectivity) to a Mobile Node (MN) on the wireless LAN. In addition, the Access Points (APs) also is configured for network connectivity to the wireless domain service (WDS) and to tunnel the mobile node's (MN) data traffic to the central switch (CS) through the wired LAN, and to communicate with the WDS for control plane signaling. The layer-3 mobility module (L3MM) on the router processor of the central switch is configured to handle the management of multi-endpoint GRE tunnels (mGRE tunnels) to the access points (APs).
Moreover, in the wireless local area network (WLAN), the wireless domain service (WDS) is configured to actively interact with the layer-3 mobility module (L3MM) and the access points (APs). That is, the wireless domain service (WDS) is configured to handle the mobile node (MN) authentication and to maintain the session states for each mobile node (MN) connected to the respective access points (APs) in the wireless local area network (WLAN).
Due to the complexity and high cost associated with providing a stateful switchover for failed wireless LAN service module (WLSM), the wireless local area networks may not be configured with wireless LAN service module redundancy support. In such a case, when the wireless LAN service module (WLSM) fails, the layer-3 mobility module running on the Route Processor and the access points (APs) starts to clean up the entries for all connected mobile nodes (MNs) and tearing down the corresponding tunnels for data traffic to and/or from the mobile nodes (MNs), while the Route Processor attempts to reset the failed wireless LAN service module (WLSM) or to switch to a stateless backup wireless LAN service module (WLSM).
This results in data traffic disruption for all mobile nodes (MNs) in the wireless local area network (WLAN) for the time period during which the wireless LAN service module (WLSM) is rebooted or initialized, and thereafter each mobile node (MN) completes its registration process with the wireless domain service (WDS) of the rebooted wireless LAN service module.
In view of the foregoing, it would be desirable to have methods and systems for providing cost effective wireless LAN service module failure recovery with no disruption to data traffic for the existing authenticated mobile nodes (MNs) during the failure and subsequent recovery, and which provides significant reduction in costs associated with development and implementation of redundant hardware to support the wireless LAN service module failure recovery process.